It's alive! (HP 25 w/Panamatik ACT)

[Peter Klein]

I'm really happy with this rebirth. My HP 25 again has storage registers, programming and several enhancements. Unsoldering the old ACT was a lot of work, but well worth it in the end. Some of the Panamatik improvements are in the realm of "how did I ever do without this?", such an annunciator for the f, g and STO keys, flicker suppression, keystrokes to display all registers and program steps in succession, and the ability to insert and delete program steps. Plus continuous memory, a plethora of program space that can be chained, and the complete set of HP Applications Programs built in.

Big thanks to Bernhard for creating the new ACT, and for being there to help when I lifted a trace off the board and didn't know where one end went. He did. A bit of fiddling with a wire patch made everything right again.

This was a sentimental project. This old '25 was my first programmable calculator. A simple program using the HMS to decimal hours functions added up many recording timings for my classical music programs on public radio way back in the '70s. The calculator helped me learn more math after college, and allowed me to practice programming skills that were indispensable when I transitioned from an impecunious arts person to an IT guy who could make a living. Yes, my other Voyagers and Pioneers are "better," but it's nice to have Calculator One working again. And there's something warm and comforting about those red LEDs. Baby's back!

   

[John Garza (3665)]

Damn fine job!

It may last another 50 years. You will get a century out that baby!
And I love the appropriate quote 'it's alive!' from Frankenstein. It's a great upgrade.

-J

[Peter Face]

I would like to second everything you say about Panamatik ACT from Bernhard. My Hp-25 is resurrected since November 2023. It is now a very happy calculator.
I am, sadly the reason my Hp-25 died as I plugged it into the charger straight out of the cupboard where it was stored for many years. Big problem which I would have been aware of had I read a bit of this forum.
Cheers
Peter

[David Hayden]

I will also second the kudos for Bernhard's Panamatik work. I have a Woodstock LP with the 34C keyboard overlay and Ir transmitter so I can print. Just last night I switched it to 67 mode with the plan to enter a User Library program (216D - Mastermind Deluxe) and print the listing since the original listing is hand written.

The panamatik is well worth the cost.

Dave

[Namir]

We are all so gratefull for Bernhard's fantatstic better-than-first-class work!!! It is giving all these calculators a new lease on life!

Namir

[PANAMATIK]

Thanks to all for the nice feedback!

Although I didn't participate in this forum for long time, because I had not much news to report, I will keep trying to send ACT repair kits to everybody who needs to revive an old Woodstock calculator. Meanwhile over some years more than 500 calculators could be repaired!

Since last year, I was forced to work again on the new ACT circuit software, because the PIC16F1518 processor was not longer available. I changed to the pin compatible PIC16F15256 processor, which has a lot of different registers. Many peripherals had to be programmed differently to get the same timing, it also runs now at double speed (now 32MHz), which was not the reason for the change and not at all necessary, but a nice to have for running programs much faster now. Then there was a lot of testing before I could be sure to send the new version to you. But meanwhile a bunch of ACTs with the new processor are sent out in the wild and behave as well as the previous version.

Bernhard

[Thomas Klemm]

(01-09-2024 05:31 PM)PANAMATIK Wrote:  Meanwhile over some years more than 500 calculators could be repaired!

That is amazing!

[Peter Klein]

We, whose Woodstocks are no longer about to die, salute you!

—Peter

[rprosperi]

Bravo Bernhard, BRAVO!!

I knew that many, many Woodstocks were brought back to life, greatly pleasing their owners by restoring what was likely their first HP machine, but had no idea the number was so impressively large!

Though creating your ACT kits was clearly a labor of love for yourself, it has also brought much joy to, well, over 500 HP users, truly worth noting.

Huge thanks once again!

[pito]

Hi, I own an HP-25 in a great condition, I added the zener protection diode and I inserted a set of new NiMH accus around the year 2000, and I've been charging the unit once per 1-3years (otherwise it sits on the bench), still the same accus inside, and, interestingly, it always works when I switch it on before the charging.
Great work with the ACT chip, congratulation!
Btw., I've been thinking to put the chip into my unit as well..

[Luro1964]

Thanks to Bernhard and the info on this forum, I'll soon be attempting to revive my dad's HP-25. The chip has arrived, will read the instructions carefully!
My question to you all is this: some corrosion from one of the batteries has eaten away at the black cardboard (?) separator at the terminals. I am not sure actually what its function is and what it is made of. I would need to make a replacement. What can I use?
Thanks in advance for any advice!

[Peter Klein]

(01-17-2024 11:26 AM)Luro1964 Wrote:  My question to you all is this: some corrosion from one of the batteries has eaten away at the black cardboard (?) separator at the terminals. I am not sure actually what its function is and what it is made of. I would need to make a replacement. What can I use?

I have seen this black cardboard-like material in many electronic devices’ battery compartments. Does anyone know what it is called, and if it is still available? Mine disappeared while I was fixing my HP-25.

My guess is that it serves to separate and insulate the battery connections from short circuiting to other parts of the device, and to catch any leakage before it touches and ruins other components.

Any replacement should be insulating, a bit absorbent, and not prone to shedding fibers that could end up in key or switch mechanisms.

[Luro1964]

I agree, Peter, it would be good if someone knows what it is made out of.
On the other hand, it sounds like you have repaired your HP-25 without a replacement and it functions OK, is that correct?

[Peter Klein]

(01-23-2024 12:53 AM)Luro1964 Wrote:  I agree, Peter, it would be good if someone knows what it is made out of.
On the other hand, it sounds like you have repaired your HP-25 without a replacement and it functions OK, is that correct?

Yes, that is correct.